Abstract
Breakwaters have been frequently constructed in Japan as one of countermeasures against coastal disasters, for instance, shore erosions, overtopping waves and so forth. However, breakwaters have been viewed with suspicions that bring about various problems. These problems are water pollution in harbor and impairing scenery. Therefore, a breakwater combining submerged breakwater and horizontal plate was chosen as a permeable breakwater, and the wave effacing effects of the breakwater were researched using transmission coefficient to know degrees of the wave effacing effects of the breakwater in this study. As a result, we found that the wave effacing effects of a breakwater depend on size and position of submerged breakwater and horizontal plate: horizontal plate set at higher level make a breakwater more effective.
